It was from out the rinde of one apple tasted, that the knowledge of good and evill as two twins cleaving together leapt forth into the World. And perhaps this is that doom which Adam fell into of knowing good and evill, that is to say of knowing good by evill. As therefore the state of man now is; what wisdome can there be to choose, what continence to forbeare without the knowledge of evill? He that can apprehend and consider vice with all her baits and seeming pleasures, and yet abstain, and yet distinguish, and yet prefer that which is truly better, he is the true wayfaring Christian. I cannot praise a fugitive and cloister’d vertue, unexercis’d & unbreath’d, that never sallies out and sees her adversary, but slinks out of the race, where that immortall garland is to be run for, not without dust and heat. Assuredly we bring not innocence into the world, we bring impurity much rather: that which purifies us is triall, and triall is by what is contrary.
John Milton (1608–1674) Areopagitica